As a solid-state imaging device, a device using CMOS technology is known, and particularly, a device using a passive pixel sensor (PPS) configuration is known. The solid-state imaging device of the PPS configuration includes a photodetecting unit in which PPS type pixels each including a photodiode that generates a charge of an amount according to an incident light intensity are arrayed two-dimensionally in M rows and N columns. This solid-state imaging device outputs a voltage value according to the amount of the charge generated in the photodiode according to light incidence in each pixel.
In general, an output terminal of each of M pixels in each column is connected to an input terminal of an integration circuit provided corresponding to the column via a readout line provided corresponding to the column. In each row sequentially from a first row to an M-th row, a charge generated in the photodiode of the pixel is input to the corresponding integration circuit via the corresponding readout line, and the voltage value according to the amount of charge is output from the integration circuit. Further, this voltage value is subjected to AD conversion to be a digital value.
The solid-state imaging device of the PPS configuration is used in various applications, for example, the device is used as an X-ray flat panel in medical applications or industrial applications in combination with a scintillator unit, and more specifically, the device is used in an X-ray CT apparatus, a microfocus X-ray inspection apparatus, or the like. An X-ray imaging system disclosed in Patent Document 1 can image X-rays output from an X-ray generating device and transmitted through an imaging object using a solid-state imaging device and image the imaging object. This X-ray imaging system can image X-rays transmitted through the imaging object in imaging modes of a plurality of types using the solid-state imaging device.